Single axle, semi-levered landing gear with shortening mechanism

ABSTRACT

A semi-levered landing gear including a shock strut configured for coupling to an airframe of an aircraft, a truck lever being rotatably coupled to the shock strut, a tension link assembly having a tension link assembly first end, a tension link assembly second end and at least one tension link assembly rotation axis, the tension link assembly first end being coupled to the shock strut, and the tension link assembly second end being coupled to the truck lever, and a positioning mechanism configured for coupling to one or more of the airframe and the shock strut and being coupled to the tension link assembly, wherein the tension link assembly is configured to rotate the truck lever about the truck pivot axis of rotation between a truck lever extended position and a truck lever stowed position.

BACKGROUND 1. Field

The exemplary embodiments generally relate to aircraft landing gearsystems and aircraft incorporating those landing gear systems and inparticular to landing gear assemblies having a shortened length forstowing the landing gear after retraction while providing the aircraftwith increased rotation on takeoff.

2. Brief Description of Related Developments

An aircraft generally includes landing gear to facilitate takeoff,landing and taxi. For takeoff and landing of the aircraft, a tallerlanding gear is desired to generate a greater angle of rotation (e.g.angle of attack) of the aircraft. The landing gear of some aircraftincludes a multi-axle truck beam pivotally coupled to a shock strut at,for example, a distal or lower end of the shock strut to achieve tallertakeoff heights; however multi-axle landing gear increases weight andcomplexity of the landing gear.

For single axle landing gear, additional ground clearance for rotationof the aircraft during takeoff is achieved by increasing the height oflanding gear. However, in order to increase the takeoff height using asingle axle landing gear, the increased length results in the landinggear being moved further outboard, from the aircraft fuselage, along thewing to compensate for the increased length of the landing gear onstowage. Further, increasing the length of the single axle landing gearincreases the static height of the aircraft resulting in the need fornew sill waterlines, longer and higher exit slides, a landing gearactuation mechanism redesign, the need for off wing exit slides, landinggear stowage compartment redesign, etc.

SUMMARY

The following is a non-exhaustive list of examples, which may or may notbe claimed, of the subject matter according to the present disclosure.

One example of the subject matter according to the present disclosurerelates to a semi-levered landing gear including a shock strut, havingan inner cylinder and an outer cylinder, the shock strut configured forcoupling to an airframe of an aircraft, a truck lever having a trucklever first end and a truck lever second end longitudinally spaced fromthe truck lever first end, the truck lever being rotatably coupled tothe shock strut about a truck pivot axis of rotation that is disposedbetween the truck lever first end and the truck lever second end, atension link assembly having a tension link assembly first end, atension link assembly second end, and at least one tension link assemblyrotation axis disposed between the tension link assembly first end andthe tension link assembly second end, the tension link assembly firstend being coupled to the shock strut outer cylinder, and the tensionlink assembly second end being coupled to the truck lever second end,and a positioning mechanism being configured for coupling to one or moreof the airframe and the shock strut and being coupled to the tensionlink assembly proximate the tension link assembly first end, wherein thetension link assembly is configured to rotate the truck lever about thetruck pivot axis of rotation between a truck lever extended position anda truck lever stowed position.

Another example of the subject matter according to the presentdisclosure relates to an aircraft including an airframe, and asemi-levered landing gear including a shock strut coupled to theairframe, a truck lever having a truck lever first end and a truck leversecond end longitudinally spaced from the truck lever first end, thetruck lever being rotatably coupled to the shock strut about a truckpivot axis of rotation that is disposed between the truck lever firstend and the trick lever second end, a tension link assembly having atension link assembly first end, a tension link assembly second end andat least one tension link assembly rotation axis disposed between thetension link assembly first end and the tension link assembly secondend, the tension link assembly first end coupled to the shock strut, andthe tension link assembly second end being coupled to the truck leversecond end, a positioning mechanism coupled to one or more of theairframe and the shock strut and being coupled to the tension linkassembly proximate the tension link assembly first end, wherein thetension link assembly is configured to rotate the truck lever about thetruck pivot axis of rotation between a truck lever extended position anda truck lever stowed position.

Still another example of the subject matter according to the presentdisclosure relates to a semi-levered landing gear including a shockstrut coupled to an airframe of an aircraft about a trunnion axis ofrotation, a retraction mechanism coupled to the airframe, a truck leverhaving a truck lever first end and a truck lever second endlongitudinally spaced from the truck lever first end, the truck leverbeing rotatably coupled to the shock strut about a truck pivot axis ofrotation that is disposed between the truck lever first end and thetruck lever second end, a tension link assembly having a tension linkassembly first end, a tension link assembly second end and at least onetension link assembly rotation axis disposed between the tension linkassembly first end and the tension link assembly second end, the tensionlink assembly first end being coupled to the shock strut, and thetension link assembly second end being coupled to the truck lever secondend, and a positioning mechanism being configured for coupling to one ormore of the airframe and the shock strut and being coupled to thetension link assembly proximate the tension link assembly first end,wherein rotation of the truck lever about the truck pivot axis ofrotation between a truck lever extended position and a truck leverstowed position is mechanically slaved to rotation of the shock strutabout the trunnion axis of rotation.

BRIEF DESCRIPTION OF THE DRAWINGS

Having thus described examples of the present disclosure in generalterms, reference will now be made to the accompanying drawings, whichare not necessarily drawn to scale, and wherein like referencecharacters designate the same or similar parts throughout the severalviews, and wherein:

FIGS. 1A-1C are schematic illustrations of an aircraft and semi-leveredlanding gear in accordance with one or more aspects of the presentdisclosure;

FIG. 2 is a schematic illustration of the semi-levered landing gear inaccordance with one or more aspects of the present disclosure;

FIG. 3 is a schematic illustration of a portion of the semi-leveredlanding gear in accordance with one or more aspects of the presentdisclosure;

FIG. 4 is a schematic illustration of a portion of the semi-leveredlanding gear in accordance with one or more aspects of the presentdisclosure;

FIG. 5 is a schematic illustration of the semi-levered landing gear in astatic height configuration, a takeoff height configuration and astowage configuration in accordance with one or more aspects of thepresent disclosure;

FIG. 6 is a schematic illustration of a portion of the semi-leveredlanding gear in accordance with one or more aspects of the presentdisclosure;

FIG. 7 is a schematic illustration of a portion of the semi-leveredlanding gear in accordance with one or more aspects of the presentdisclosure;

FIG. 8 is a schematic illustration of the aircraft and the semi-leveredlanding gear in accordance with one or more aspects of the presentdisclosure;

FIG. 9 is graph illustrating the ground contact vertical load of thesemi-levered landing gear versus the shock stilt stroke of thesemi-levered landing gear in accordance with one or more aspects of thepresent disclosure; and

FIG. 10 is a flowchart of a method for operating the semi-leveredlanding gear shown in FIGS. 1 to 8.

DETAILED DESCRIPTION

In order to achieve a greater angle of attack/rotation of the aircrafton takeoff and/or landing, maintain current static ride heights andcurrent attachment locations of a conventional landing gear, withouthaving to redesign the aircraft, the semi-levered landing gear describedherein increases height of the aircraft during takeoff and shortens alength of the landing gear in a stowing position following takeoff forstowage in the current landing gear bay with little to no modificationof the aircraft. In particular, the semi-levered landing gear describedherein is both weight and cost efficient and is not overly complex,while still satisfying the static height, takeoff and/or landing heightand stowage requirements of the semi-levered landing gear.

The embodiments described herein provide a single axle, semi-leveredlanding gear with a pivoting truck link and a landing gear lengthshortening mechanism which generally has a simple configuration thatprovides a low static ride height of the aircraft, a tall takeoff heightof the aircraft and a shortened landing gear length for stowage of thelanding gear within the aircraft.

Illustrative, non-exhaustive examples, which may or may not be claimed,of the subject matter according to the present disclosure are providedbelow.

Referring to FIGS. 1A-1C and 2 an exemplary aircraft 100 andsemi-levered landing gear 200 with a shortening mechanism 201 isillustrated incorporating aspects of the present disclosure.

In one aspect, while the semi-levered landing gear 200 described hereinis described with respect to a commercial passenger jet, referred toherein as the aircraft 100, in other aspects the aircraft may be anysuitable aircraft having a fixed wing or variable sweep wing Thesemi-levered landing gear 200 may also be used in landing gear havingany suitable position on the aircraft 100, such as landing gear 200A,which may be a main landing gear, located towards a longitudinal centerof the aircraft 100, or in other aspects a nose landing gear 200Blocated towards a longitudinal front of the aircraft 100. As will bedescribed herein, the semi-levered landing gear 200 is configured tocouple to one or more of the airframe 101 and the landing gearcomponents (e.g., a landing gear hydraulic actuator, landing gearextension/retraction mechanisms/linkages etc.) of the aircraft 100 forproviding the low static ride height, the tall take-off height and theshortened length for retraction of the semi-levered landing gear 200.

Referring to FIGS. 1B and 1C, the semi-levered landing gear 200 isillustrated in an extended and stowed position. A conventional singleaxle landing gear 102 is also illustrated for comparison of the landinggear attachment locations relative to the airframe 101 of the aircraft100. In one aspect, the semi-levered landing gear 200 provides the samestatic ride height A (e.g. the distance from the ground to the lowestpoint on the aircraft 100 such as the bottom of the fuselage 100F) asthe conventional single axle landing gear 102 while being coupled to theairframe 101 further inboard, relative to the centerline CL of thefuselage 100F by a predetermined distance B. As can be seen best in FIG.1B, upon retraction, the location of the landing gear wheel(s) 204 andWheel axis WA are located at a common location (e.g. within the wheelcompartment of the aircraft 100 with little to no modification of thewheel bay) as illustrated by the retraction path 102A of theconventional single axle landing gear 102 and the retraction path 200Rof the semi-levered landing gear 200. As such, the semi-levered landinggear 200 may be fit to an aircraft while maintaining the existingconventional landing gear bay of the aircraft, sill waterlines, etc.,i.e., the aircraft 100 does not have to be redesigned in order toaccommodate the semi-levered landing gear 200 and receive the increasedtakeoff and/or landing height and aircraft rotation benefits of thesemi-levered landing gear 200.

The semi-levered landing gear 200 in accordance with the aspects of thepresent disclosure provides for a landing gear system with lesscomplexity when compared to other, conventional landing gear shorteningdesigns (such as hydraulics that compress the shock strut uponretraction and stowage of the landing gear), reduced weight compared toconventional landing gear shortening designs, and contains less storedenergy than conventional landing gear shortening designs that performthe same or similar function (e.g., shortening the landing gear forretraction into the aircraft). For example, the semi-levered landinggear 200 can be shortened for stowage within the aircraft withoutcompression of the shock strut 210 of the semi-levered landing gear 200.

Referring to FIGS. 2 and 3, in one aspect and as noted above, thesemi-levered landing gear 200 is a single axle landing gear thatincludes a shock strut 210, a truck lever 220, a tension link assembly230, and a positioning mechanism 240 (the tension link assembly 230coupled to the positioning mechanism 240 is also referred to hereinafteras a shortening mechanism 201). In one aspect, the semi-levered landinggear 200 includes at least one wheel 204. In one aspect, the at leastone wheel 204 is disposed on a common (e.g. single) axle of thesemi-levered landing gear. For example, in one aspect, the at least onewheel 204 includes two or more wheels disposed on the common axle. Inone aspect, the semi-levered landing gear 200 also includes a trunnion203 coupled to the shock strut 210 where the trunnion 203 is pivotallycoupled to the airframe 101 (see FIG. 1C) so that the semi-leveredlanding gear 200 pivots about a trunnion axis of rotation TAR between alanding gear stowed position and a landing gear extended position. Inone aspect, any suitable hydraulics and actuation mechanisms/linkage maybe coupled to semi-levered landing gear 200 for actuation of thesemi-levered landing gear 200. In one aspect, the landing gear actuationmechanism includes a retraction mechanism 202 to which the shorteningmechanism 201 is coupled as described herein.

In one aspect, the shock strut 210 includes an outer cylinder 211 and aninner cylinder 212 that is movable relative to the outer cylinder 211.In one aspect, the shod(stint 210 may be gas over oil shock, while inother aspects the shock strut 210 may include any suitabledampening/rebound mechanism. In one aspect, the inner cylinder 212 movesrelative to the outer cylinder 211 to compress and un-compress/extendthe shock strut 210 under, the weight of the aircraft 100. In oneaspect, the shock strut 210 also includes a rotation stop 213 thatinteracts with the shortening mechanism 201 as described herein. In oneaspect, the rotation stop 213 is the outer cylinder 211 while in otheraspects the rotation stop 213 may be coupled to the outer cylinder 211in any suitable manner. In one aspect, the rotation stop 213 is ofunitary one piece construction with the outer cylinder 211 of the shockstrut 210. In one aspect, as noted above, trunnion 203 is coupled to theouter cylinder 211 of the shock stint 210 so that the outer cylinder 211is coupled to the airframe 101 of the aircraft 100. In one aspect, theouter cylinder 211 of the shock strut 210 and the trunnion 203 areformed as a unitary one piece member.

Still referring to FIGS. 2 and 3, in one aspect, the truck lever 220 hasa truck lever first end 220 a and a truck lever second end 220 blongitudinally spaced from the truck lever first end 220 a. In oneaspect, the truck lever 220 is a rigid member, i.e., there are noarticulated joints between the truck lever first end 220 a and the trucklever second end 220 b. In one aspect, the truck lever 220 comprises amonolithic member. In one aspect, the truck lever 220 is pivotallycoupled to the inner cylinder 212 about a truck pivot axis of rotationTPA disposed between the truck lever first end 220 a and the truck leversecond end 220 b. In one aspect, as noted above, the truck lever 220includes but one wheel axis WA that is disposed proximate the trucklever first end 220 a between the truck lever first end 220 a and thetruck pivot axis of rotation TPA. In one aspect, the shock strut 210 issubstantially uncompressed with the truck lever 220 at the truck leverextended position (see e.g. the takeoff height configuration illustratedin FIG. 5). In one aspect, the shock strut 210 is substantiallyuncompressed with the truck lever 220 at the truck lever stowed position(see e.g. the stowage height configuration illustrated in FIG. 5).

Still referring to FIGS. 2 and 3, the shortening mechanism 201 includesa tension link assembly 230 and a positioning mechanism 240. In oneaspect, the tension link assembly 230 includes a tension link assemblyfirst end 230 a, a tension link assembly second end 230 b, and at leastone tension link assembly rotation axis TLA disposed between the tensionlink assembly first end 230 a and the tension link assembly second end230 b. In one aspect, the tension link assembly 230 is coupled to boththe truck lever 220 and the shock strut 210. For example, in one aspect,the tension link assembly first end 230 a is rotatably coupled to theouter cylinder 211 of the shock strut 210 in any suitable manner such asabout an over-center pivot axis OPA. In one aspect, the tension linkassembly 230 is configured so that the truck lever 220 rotates about thetruck pivot axis of rotation TPA during compression and rebound of theshock strut 210 to provide for normal operation (e.g. the compressionand rebound) of the shock strut as well as to provide the increasedtakeoff height of the aircraft 100. The tension link assembly 230 isalso configured so that the truck lever 220 rotates about the truckpivot axis of rotation TPA to the stowed configuration (see FIG. 5) uponretraction and stowage of the semi-levered landing gear 200.

Referring to FIGS. 2, 3 and 4, in one aspect, the tension link assembly230 includes an over-center link 231 and a truck link 232. In oneaspect, the tension link assembly 230 may include any suitable number oflinks. The over-center link 231 includes an over-center link first end231 a and an over-center link second end 231 b longitudinally spacedfrom the over-center link first end 231 a. In one aspect, theover-center link first end 231 a defines the tension link assembly firstend 230 a and is rotatably coupled to the shock strut 210 about theover-center pivot axis OPA in any suitable manner.

In one aspect, the truck link 232 includes a truck link first end 232 aand a truck link second end 232 b longitudinally spaced from the trucklink first end 232 a. In one aspect, the truck link first end 232 a isrotatably coupled to the over-center link second end 231 b about thetension link assembly rotation axis TLA so that the truck link 232 andthe over-center link 231 are configured to fold and unfold relative toeach other about the tension link assembly rotation axis TLA. In oneaspect, the truck link second end 232 b defines the tension linkassembly second end 230h and is rotatably coupled to the truck leversecond end 220 b in any suitable manner about axis AX5. The truck linksecond end 232 b is rotatably coupled to the truck lever second end 220b such that the truck link 232 and the truck lever 220 fold and unfoldrelative to each other. The truck link 232 folding and unfoldingrelative to the truck lever 220 rotates the truck lever 220 about thetruck pivot axis of rotation TPA between a truck lever extended positionand a truck lever stowed position and to provide operation of thesemi-levered landing gear 200 such as during compression and rebound ofthe shock strut 210. With the truck link 232 unfolded relative to thetruck lever 220, the tension link assembly 230 is at a shortest length(as will be further described below) rotating the truck lever such thatthe at least one wheel 204 is further away from the trunnion axis ofrotation TAR (i.e., during compression and rebound). With the truck link232 folded relative to the truck lever 220, the tension link assembly230 is at a longest length (as will be further described below) rotatingthe truck lever 220 such that the at least one wheel 204 is closer tothe trunnion axis of rotation (i.e., stowed). The truck link 232 isconfigured to provide a tension load to resist a moment M that rotatesthe truck lever 220 about the truck pivot axis of rotation TPA createdby a vertical force VF applied to the at least one wheel 204 by theground, where the inner cylinder 212 provides an opposing a force VF1 tothe at least one wheel 204 that opposes the vertical force VF.

Referring again to FIG. 2, in one aspect, the positioning mechanism 240includes a number of links coupled to one or more of the shock strut210, the airframe 101 and the tension link assembly 230. The positioningmechanism 240 is provided to lock or unlock, as will be describedfurther herein, the tension link assembly 230 where, when locked, thetension link assembly 230 resists the moment M applied to the trucklever 220 about the truck pivot axis of rotation TPA and where unlockedthe truck lever 220 is positioned for stowage of the semi-leveredlanding gear 200 in the landing gear bay of the aircraft 100. In oneaspect, the number of links of the positioning mechanism 240mechanically slave the orientation of the tension link assembly 230 tothe extension and retraction of the semi-levered landing gear 200 fromand to its stowed position within the landing gear bay of the aircraft100. In one aspect, the positioning mechanism 240 may not bemechanically slaved to the extension and retraction of the semi-leveredlanding gear 200 from and to its stowed position within the landing gearbay of the aircraft 100. For example, here the positioning mechanism 240may include a linear actuator coupled to the outer cylinder 211 and theover-center link 231. In one aspect, the linear actuator is one of ahydraulic ram, a pneumatic ram, a ball screw actuator, or a solenoid. Inone aspect, the linear actuator is any suitable type of actuator. In oneaspect, the positioning mechanism 240 may include a circular rotationactuator coupled to the outer cylinder 211 and the over-center link 231.In one aspect, the circular rotation actuator is one of a stepper motoror an electric motor. In one aspect, the circular rotation actuator isany suitable circular rotation actuator.

Referring to FIGS. 2, 3 and 4, in one aspect, the number of links of thepositioning mechanism 240 includes a connecting link 241, a first pivotlink 242, and a second pivot link 243. The connecting link 241 includesa connecting link first end 241 a and a connecting link second end 241b. In one aspect, the connecting link 241 is a rigid link (e.g.unarticulated so that there are no articulated joints between theconnecting link first and second ends 241 a, 241 b). In one aspect, theconnecting link first end 241 a is coupled to the airframe 101 of theaircraft 100 such as by rotatably coupling the connecting link first end241 a to the retraction mechanism 202 so that the positioning of thetruck lever 220 by the shortening mechanism 201 is mechanically slavedto the extension and retraction of the semi-levered landing gear 200 toand from the landing gear bay of the aircraft 100. In one aspect, wherethe positioning of the truck lever 220 is not mechanically slaved, theconnecting link first end 241 a may be coupled to the shock strut 210,such as to the outer cylinder 211 and be in the farm of a linearactuator as described above. In one aspect, the connecting link secondend 241 b is coupled to the first pivot link 242 or the second pivotlink 243 about axis AX4.

In one aspect, the first pivot link 242 includes a first end 242 a and asecond end 242 b longitudinally spaced from the first end 242 a. Thefirst end 242 a of the first pivot link 242 is rotatably coupled to theshock strut 210, such as to the outer cylinder 211, in any suitablemanner. In one aspect, the connecting link second end 241 b is coupledto the second end 242 b of the first pivot link 242 about the axis AX4.

In one aspect, the second pivot link 243 includes a first end 243 a anda second end 2436 longitudinally spaced from the first end 243 a. Thefirst end 243 a of the second pivot link 243 is rotatably coupled to thesecond end 242 b of the first pivot link 242 about axis AX4. In oneaspect, the connecting link second end 241 b is coupled to the first end243 a of the second pivot link 243 about axis AX4. The first pivot link242 and the second pivot link 243 fold and unfold relative to eachother. The second end 243 b of the second pivot link 243 is rotatablycoupled to the over-center link 231 proximate the over-center linksecond end 231 b so that folding and unfolding of the first pivot link242 relative to the second pivot link 243, caused by connecting link241, rotates the tension link assembly rotation axis TLA in directionR1, R2 about the over-center pivot axis OPA to lock and unlock thetension link assembly 230. In one aspect, the over-center link 231includes one or more protrusions 231P that extend laterally away from acenterline CLC of the over-center link 231 in a direction away from theshock strut 210. The second end 243 b of the second pivot link 243 iscoupled to the one or more protrusions 231P so that force applied by thesecond pivot link 243 to the over-center link 231 is applied off-centerrelative to the over-center pivot axis OPA so that a moment is producedabout the over-center pivot axis OPA for rotating the tension linkassembly rotation axis TLA in direction R1, R2 about the over-centerpivot axis OPA to lock and unlock the tension link assembly 230.

Referring now to FIGS. 2-7, operation of the semi-levered landing gear200 will now be described with respect to the aircraft 100. As can beseen best in FIG. 5, as the weight of the aircraft 100 rests on thesemi-levered landing gear 200, the shock strut 210 is in a staticallycompressed state (noting that there remains travel within the shockstrut to cushion the aircraft 100 for dynamic loading during taxi),hereafter referred to as the statically compressed shock strut 210A.With the statically compressed shock strut 210A in the staticallycompressed state the truck lever 220 is rotated about the truck pivotaxis of rotation TPA so that the truck lever 220 is oriented in a staticride height configuration, hereinafter the static ride height trucklever 2201, to provide the aircraft with the static ride height A (FIG.10, Block 1200). As described above, with the static ride height trucklever 2201 at the static ride height configuration the aircraft 100 isprovided with a static ride height A that is the same as the static rideheight A of the aircraft 100 when equipped with conventional single axlelanding gear 102.

Here, with the semi-levered landing gear 200 in the static height andtakeoff height configurations, as illustrated in FIG. 5, the shorteningmechanism 201 is in an over center locked configuration 201A, e.g., theover-center link second end 231 b of the over-center link 231 is heldagainst the rotation stop 213 of the outer cylinder 211 in direction R1by the tension forces acting on truck link 232 due to, for example, thevertical force VF acting upon the semi-levered landing gear 200 (FIG.10, Block 1205). In the over center locked configuration 201A, thetension link assembly 230 is able to react the tension load to the outercylinder 211 of the statically compressed shock strut 210A through therotation stop 213 and the point at which the over-center link 231couples to the outer cylinder 211 of the statically compressed shockstrut 210A. The tension load tends to rotate the over-center link 231about the over-center pivot axis OPA in the rotation direction R1 towardthe rotation stop 213 on the outer cylinder 211 of the staticallycompressed shock strut 210A because the line of action of the tensionload, through the truck link 232, in the over center lockedconfiguration 201A is between the rotation stop 213 and the over-centerpivot axis OPA of the over-center link 231. As such, the tension loadand resulting moments on the tension link assembly 230 are isolated fromthe positioning mechanism 240.

As the aircraft 100 accelerates down the runway, the wings create lift.The lift created reduces the portion of the weight of the aircraft 100applied to the semi-levered lauding gear 200. The reduction in weightapplied to the semi-levered landing gear 200 causes the shock strut 210to extend or uncompress. Movement of the inner cylinder 212 of the shockstrut 210 relative to the outer cylinder 211 during extension causes thestatic ride height truck lever 2201 to rotate to a takeoff heightposition, referred to as extended truck lever 2202, as seen best in FIG.5 which provides the aircraft 100 with additional height X relative tothe static ride height A of the aircraft 100 (e.g. the static rideheight A is increased by height X at the takeoff height) (FIG. 10, Block1210). The additional height X, which is greater than the amount ofextension provided by the shock strut 210, provides for a predeterminedangle of rotation θ of the aircraft 100 relative to the ground GR, asseen in FIG. 8, upon takeoff and provides for a predetermined angle ofrotation α (e.g. angle of attack) of the aircraft 100 relative to groundGR upon landing. Here the angles of rotation θ, α are increased comparedto takeoff and landing angles of rotation θ′, α′ of the aircraft 100when equipped with conventional single axle landing gear 102 Where wheeltravel is limited only by an amount of travel of the shock strut and thedistance Z between the ground contact patch of the wheel(s) 204 and atail skid pad 800 of the aircraft remains the same for the aircraft 100.

The statically compressed shock strut 210A generally un-compresses untilthe at least one wheel 204 is off the ground, i.e., the vertical forceVF is no longer acting upon the semi-levered landing gear 200. As thestatically compressed shock strut 210A un-compresses, the shorteningmechanism 201 remains in the over center locked configuration 201A and,as described above, causes the truck lever 220 to pivot about the truckpivot axis of rotation TPA in the rotation direction R3 to, at least,the truck lever extended position. The pivot of the truck lever 220about the truck pivot axis of rotation TPA in the rotation direction R3provides a predetermined amount of ground contact vertical load so thatthe aircraft 100 rotates to the rotation angle. In one aspect, thesemi-levered landing gear 200 with an uncompressed shock strut 210B andthe shortening mechanism 201 in the over center locked configuration201A with an extended truck lever 2202, results in a first length L1between the over-center link first end 231 a over-center pivot axis OPA)and the truck link second end 232 b (e.g. axis AX5) which provides apredetermined distance L3 between the but one wheel axle WA and thetrunnion 203 (e.g. the trunnion axis of rotation TAR where thesemi-levered landing gear 200 is coupled to the airframe 101) thatresults in a larger amount of wheel travel during takeoff when comparedto the conventional single axle landing gear 102. The extended wheeltravel provided by the distance L3 between the but one wheel axle WA andthe trunnion axis of rotation TAR provides the aircraft 100 with anincreased takeoff height (compared to the takeoff height of theconventional single axle landing gear 102 whose travel is limited solelyby the extension of the shock strut) and an increased angle of rotationθ (e.g. angle of attack), again compared to conventional single axlelanding gear 102, illustrated in FIG. 1B.

After taking off, the semi-levered landing gear 200 is retracted intothe landing gear bay of the aircraft 100 (FIG. 10, Block 1215). As theweight of the aircraft 100 is no longer acting upon the semi-leveredlanding gear 200, the shock strut 210B is uncompressed (e.g. without anyvertical load VF acting on the semi-levered landing gear 200). Theuncompressed shock strut 210B pivots about the trunnion axis of rotationTAR of the trunnion 203 towards the shock strut stowed positionillustrated in FIGS. 1B and 1C. In order to stow the semi-leveredlanding gear 200, as the uncompressed shock strut 210B pivots about thetrunnion axis of rotation TAR the semi-levered landing gear 200 isshortened to fit in the substantially unmodified landing gear bay (FIG.10, Block 1220). For example, the tension link assembly 230 is movedfrom an over center locked configuration 201A to an unlockedconfiguration 201B. In one aspect, the over-center link 231 is rotatedby the positioning mechanism 240 from the locked position to theunlocked position, i.e., the over-center link 231 is rotated, by forexample, the connecting link 241 away from the rotation stop 213 inrotation direction R2 about the over-center pivot axis OPA until thedistance between the tension link assembly first end 230 a and thetension link assembly second end 230 b is a second length L2. Generally,the first length L1 is shorter than the second length L2. The secondlength L2 causes the distance between the but one wheel axle WA and thetrunnion axis of rotation TAR to be decreased from about distance L3 todistance L4. The distance L4 between the but one wheel axle WA and thetrunnion axis of rotation TAR places the truck lever 220 in a stowedconfiguration for the landing gear to be stowed into, for example, theexisting landing gear bay within the aircraft 100 with little to nomodification of the landing gear bay.

As noted above, the rotation of the over-center link 231 from lockedposition to unlocked position is controlled by the positioning mechanism240. In order to change the orientation of the over-center link 231 fromlocked position to unlocked position, the positioning mechanism 240, forexample, pushes or actuates the truck link first end 232 a in rotationdirection R2. In one aspect, as described above, the positioningmechanism 240 is mechanically slaved to the retraction of thesemi-levered landing gear 200 into the landing gear bay of the aircraft100 while in other aspects the positioning mechanism 240 is actuatedindependent of the retraction of the semi-levered landing gear into thelanding gear bay of the aircraft 100. As the truck link first end 232 aand the over-center link second end 231 b are coupled about the tensionlink assembly rotation axis TLA, the over-center link second end 231 bis also pushed or actuated in rotation direction R2 about theover-center pivot axis OPA. As the truck link first end 232 a and theover-center link second end 231 b rotate in direction R2, the trucklever 220 is rotated about the truck pivot axis of rotation TPA inrotation direction R4 to the truck lever stowed position, as illustratedin FIG. 5, which shortens the semi-levered landing gear 200 a distance Yrelative to the semi-levered landing gear 200 with a substantiallyuncompressed shock strut 210B and with the shortening mechanism 201 inthe over center locked configuration 201A with an extended truck lever2202. Shortening the semi-levered landing gear 200 through rotation ofthe truck lever 220 about the truck pivot axis of rotation TPA inrotation direction R4 to the truck lever stowed position provides forpositioning of the trunnion axis of rotation TAR closer to thecenterline CL of the aircraft 100 compared to an aircraft having aconventional single axle shock strut 102 with the same uncompressedlength at stowage as illustrated in FIGS. 1B and 1C.

Upon aircraft 100 approach for landing, the semi-levered landing gear200 is extended from the landing gear bay of the aircraft 100 (FIG. 10,Block 1225). The uncompressed shock strut 210B pivots about the trunnionaxis of rotation TAR of the trunnion 203 towards the shock strutextended position. As the uncompressed shock strut 210E pivots the aboutthe trunnion axis of rotation TAR, the truck lever 220 of thesemi-levered landing gear 200 extends the distance Y in a mannersubstantially opposite to that described above with respect to theretraction of the semi-levered landing gear 200 to the stowedconfiguration within the landing gear bay of the aircraft 100. Forexample, the positioning mechanism 240 pulls or actuates the truck linkfirst end 232 a in rotation direction R1. As the truck link first end232 a and the over-center link second end 231 b are coupled about thetension link assembly rotation axis TLA, the over-center link second end231 b is also pulled or actuated in rotation direction R1 about theover-center pivot axis OPA. As the truck link first end 232 a and theover-center link second end 231 b rotate in direction R1, the trucklever 220 is rotated about the truck pivot axis of rotation TPA inrotation direction R3 to the extended truck lever position, asillustrated in FIGS. 2 and 5.

Referring now to FIG. 9, a graph for the semi-levered landing gear 200is illustrated showing the ground contact vertical load (e.g. VF) versusthe shock strut stroke. It is noted that the shock strut stroke in FIG.9 is measured from the extended configuration of the shock strut 210 sothat as the shock strut is compressed the ground contact vertical loadis increased. As is known in the art, in order for an aircraft to takeoff, there must be enough force translation through the wheel(s) 204into the aircraft 100 for the aircraft 100 to pivot about the wheel(s)204 for takeoff and landing. As the shock strut 210 of the semi-leveredlanding gear 200 extends or un-compresses during takeoff, the groundcontact vertical load decreases. However, as can be seen by the curvePin FIG. 9 there is sufficient ground contact vertical force translatingthrough the wheels 204 with the shock strut 210 uncompressed and thetruck lever 220 extended (e.g. the extended load region of the curve P)to get a reaction between the ground and the semi-levered landing gear200 to create a moment for the aircraft 100 to pivot, noting that as theshock strut stroke increases the compression of the shock strutincreases (as shown in FIG. 9).

The following are provided in accordance with the aspects of the presentdisclosure:

A1. A semi-levered landing gear comprising:

a shock strut, having an inner cylinder and an outer cylinder, the shockstrut configured for coupling to an airframe of an aircraft;

a truck lever having a truck lever first end and a truck lever secondend longitudinally spaced from the truck lever first end, the trucklever being rotatably coupled to the shock strut about a truck pivotaxis of rotation that is disposed between the truck lever first end andthe truck lever second end;

a tension link assembly having a tension link assembly first end, atension link assembly second end, and at least one tension link assemblyrotation axis disposed between the tension link assembly first end andthe tension link assembly second end, the tension link assembly firstend being coupled to the shock strut outer cylinder, and the tensionlink assembly second end being coupled to the truck lever second end;and

a positioning mechanism being configured for coupling to one or more ofthe airframe and the shock strut and being coupled to the tension linkassembly proximate the tension link assembly first end;

wherein the tension link assembly is configured to rotate the trucklever about the truck pivot axis of rotation between a truck leverextended position and a truck lever stowed position.

A2. The semi-levered landing gear of paragraph A1, wherein the shockstrut is substantially uncompressed with the truck lever at the trucklever extended position and with the truck lever at the truck leverstowed position.

A3. The semi-levered landing gear of paragraph A1, wherein the tensionlink assembly is configured so that the truck lever rotates about thetruck pivot axis of rotation during compression of the shock strut.

A4. The semi-levered landing gear of paragraph A1, wherein the tensionlink assembly comprises:

an over-center link having an over-center link first end and anover-center link second end longitudinally spaced from the over-centerlink first end, the over-center link first end defining the tension linkassembly first end and being rotatably coupled to the shock strut aboutan over-center pivot axis; and

a truck link having a truck link first end and a truck link second endlongitudinally spaced from the truck link first end, the truck linkfirst end being rotatably coupled to the over-center link second endabout the tension link assembly rotation axis and the truck link secondend defining the tension link assembly second end and being rotatablycoupled to the truck lever second end.

A5. The semi levered landing gear of paragraph A4, wherein thepositioning mechanism comprises:

a connecting lurk having a connecting link first end and a connectinglink second end, the connecting link first end being configured forcoupling to one or more of the airframe and the shock strut;

a first pivot link having a first end and a second end longitudinallyspaced from the first end, the first end of the first pivot link beingrotatably coupled to the shock strut; and

a second pivot link having a first end and a second end longitudinallyspaced from the first end, the first end of the second pivot link beingrotatably coupled to the second end of the first pivot link;

wherein the connecting link second end is coupled to at least one ofproximate the second end of the first pivot link and proximate the firstend of the second pivot link.

A6. The semi-levered landing gear of paragraph A5, wherein:

the second end of the second pivot link is rotatably coupled to theover-center link proximate the over-center link second end so thatmovement of the connecting link causes rotation of the truck link firstend about the over-center pivot axis.

A7. The semi-levered landing gear of paragraph A5, wherein theconnecting link comprises a linear actuator and the connecting linkfirst end is coupled to the shock strut or the airframe.

A8. The semi-levered landing gear of paragraph A5, wherein theconnecting link comprises a hydraulic actuator and the connecting linkfirst end is coupled to the shock strut or the airframe.

A9. The semi-levered landing gear of paragraph A5, wherein theconnecting link is a rigid unarticulated link.

A10. The semi-levered landing gear of paragraph A1 further comprising:

a retraction mechanism coupled to the airframe;

wherein the shock strut includes a trunnion, the trunnion beingrotatably coupled to the airframe at a trunnion axis of rotation so thatthe shock strut rotates about the trunnion axis of rotation between ashock strut stowed position and a shock strut extended position relativeto the airframe; and

wherein the positioning mechanism is coupled to the retraction mechanismso that rotation of the truck lever about the truck pivot axis ofrotation, between the truck lever extended position and the truck leverstowed position, is mechanically slaved to rotation of the shock strutabout the trunnion axis of rotation.

A11. The semi-levered landing gear of paragraph A1, Wherein the trucklever includes but one wheel axis.

A12. The semi-levered landing gear of paragraph A11, wherein the but onewheel axis is proximate the truck lever first end.

A13. The semi-levered landing gear of paragraph A1, wherein rotation ofthe truck lever to the truck lever extended position provides theaircraft with a greater angle of attack at takeoff compared to anaircraft having a same length and but one wheel axis on a shock strut.

A14. The semi-levered landing gear of paragraph A1, wherein rotation ofthe truck lever about the truck pivot axis of rotation provides theaircraft with a same static ground height compared to an aircraft havinga same length and but one wheel axis on a shock strut.

A15. The semi-levered landing gear of paragraph A1 wherein rotation ofthe truck lever to the truck lever stowed position provides forpositioning of a trunnion axis of rotation of the shock strut closer toa longitudinal centerline of the aircraft compared to an aircraft havinga shock strut stroke with a same uncompressed length at stowage.

A16. The semi-levered landing gear of paragraph A1, wherein with thetruck lever in the truck lever extended position, the semi-leveredlanding gear provides the aircraft with a predetermined amount of groundcontact vertical load so that the aircraft rotates to a greater angle ofattack at takeoff compared to an aircraft having a same length shockstrut and but one wheel axis on the shock strut.

A17. The semi-levered landing gear of paragraph A1, wherein:

the inner cylinder is movable relative to the outer cylinder; and

the truck lever is rotatably coupled to either the inner cylinder or theouter cylinder.

A18. The semi-levered landing gear of paragraph A1, wherein the trucklever comprises a monolithic member.

B1. An aircraft comprising:

an airframe; and

a semi-levered landing gear including

a shock strut coupled to the airframe;

a truck lever having a truck lever first end and a truck lever secondend longitudinally spaced from the truck lever first end, the trucklever being rotatably coupled to the shock strut about a truck pivotaxis of rotation that is disposed between the truck lever first end andthe truck lever second end;

a tension link assembly having a tension link assembly first end, atension link assembly second end and at least one tension link assemblyrotation axis disposed between the tension link assembly first end andthe tension link assembly second end, the tension link assembly firstend coupled to the shock strut, and the tension link assembly second endbeing coupled to the trick lever second end;

a positioning mechanism coupled to one or more of the airframe and theshock strut and being coupled to the tension link assembly proximate thetension link assembly first end;

wherein the tension link assembly is configured to rotate the trucklever about the truck pivot axis of rotation between a truck leverextended position and a truck lever stowed position.

B2. The aircraft of paragraph B1, wherein rotation of the truck lever tothe truck lever extended position provides the aircraft with a greaterangle of attack at takeoff compared to an aircraft having a same lengthand but one wheel axis on a shock strut.

B3. The aircraft of paragraph B1, wherein rotation of the truck leverabout the truck pivot axis of rotation provides the aircraft with a samestatic ground height compared to an aircraft having a same length shockstrut and but one wheel axis on the shock strut.

B4. The aircraft of paragraph B1, wherein rotation of the truck lever tothe truck lever stowed position provides for positioning of a trunnionaxis of rotation of the shock strut closer to a longitudinal centerlineof the aircraft compared to an aircraft having a shock strut stroke witha same uncompressed length at stowage.

B5. The aircraft of paragraph B1, wherein with the truck lever in thetruck lever extended position, the semi-levered landing gear providesthe aircraft with a predetermined amount of ground contact vertical loadso that the aircraft rotates to a greater angle of attack at takeoffcompared to an aircraft having a same length and but one wheel axis on ashock strut.

B6. The aircraft of paragraph B1, wherein the shock strut issubstantially uncompressed with the truck lever at the truck leverextended position and with the truck lever at the truck lever stowedposition.

B7. The aircraft of paragraph B1, wherein the tension link assembly isconfigured so that the truck lever rotates about the truck pivot axis ofrotation during compression of the shock strut.

B8. The aircraft of paragraph B1, wherein the tension link assemblycomprises:

an over-center link having an over-center link first end and anover-center link second end longitudinally spaced from the over-centerlink first end, the over-center link first end defining the tension linkassembly first end and being rotatably coupled to the shock strut aboutan over-center pivot axis; and

a truck link having a truck link first end and a truck link second endlongitudinally spaced from the truck link first end, the truck linkfirst end being rotatably coupled to the over-center link second endabout the tension link assembly rotation axis and the truck link secondend defining the tension link assembly second end and being rotatablycoupled to the truck lever second end.

B9. The semi-levered landing gear of paragraph B8, wherein thepositioning mechanism comprises:

a connecting link having a connecting link first end and a connectinglink second end, the connecting link first end coupled to one or more ofthe airframe and the shock strut;

a first pivot link having a first end and a second end longitudinallyspaced from the first end, the first end of the first pivot link beingrotatably coupled to the shock strut; and

a second pivot link having a first end and a second end longitudinallyspaced from the first end, the first end of the second pivot link beingrotatably coupled to the second end of the first pivot link;

wherein the connecting link second end is coupled to at least one ofproximate the second end of the first pivot link and proximate the firstend of the second pivot link.

B10. The aircraft of paragraph B9, wherein:

the second end of the second pivot link is rotatably coupled to theover-center link proximate the over-center link second end so thatmovement of the connecting link causes rotation of the truck link firstend about the over-center pivot axis.

B11. The aircraft of paragraph B5, wherein the connecting link comprisesa linear actuator and the connecting link first end is coupled to theshock strut or the airframe.

B12. The aircraft of paragraph B8, wherein the connecting link comprisesa hydraulic actuator and the connecting link first end is coupled to theshock strut or the airframe.

B13. The aircraft of paragraph B5, wherein the connecting link is arigid unarticulated link.

B14. The aircraft of paragraph B1, further comprising:

a retraction mechanism coupled to the airframe;

wherein the shock strut includes a trunnion, the trunnion beingrotatably coupled to the airframe at a trunnion axis of rotation so thatthe shock strut rotates about the Trunnion axis of rotation between ashock strut stowed position and a shock strut extended position relativeto the airframe; and

wherein the positioning mechanism is coupled to the retraction mechanismso that rotation of the truck lever about the truck pivot axis ofrotation, between the truck lever extended position and the truck leverstowed position, is mechanically slaved to rotation of the shock strutabout the trunnion axis of rotation.

B15. The aircraft of paragraph B1, wherein the truck lever includes butone wheel axis.

B16. The aircraft of paragraph B15, wherein the but one wheel axis isproximate the truck lever first end.

B17. The aircraft of paragraph B1, wherein:

the shock strut comprises an outer cylinder and an inner cylinder, wherethe inner cylinder is movable relative to the outer cylinder; and

the truck lever is rotatably coupled to either the inner cylinder or theouter cylinder.

B18. The aircraft of paragraph B1, wherein the truck lever comprises amonolithic member.

C1. A semi-levered landing gear comprising:

a shock strut coupled to an airframe of an aircraft about a trunnionaxis of rotation;

a retraction mechanism coupled to the airframe;

a truck lever having a truck lever first end and a truck lever secondend longitudinally spaced from the truck lever first end, the trucklever being rotatably coupled to the shock strut about a truck pivotaxis of rotation that is disposed between the truck lever first end andthe truck lever second end;

a tension link assembly having a tension link assembly first end, atension link assembly second end and at least one tension link assemblyrotation axis disposed between the tension link assembly first end andthe tension link assembly second end, the tension link assembly firstend being coupled to the shock strut, and the tension link assemblysecond end being coupled to the truck lever second end; and

a positioning mechanism being configured for coupling to one or more ofthe airframe and the shock strut and being coupled to the tension linkassembly proximate the tension link assembly first end;

wherein rotation of the truck lever about the truck pivot axis ofrotation between a truck lever extended position and a truck leverstowed position is mechanically slaved to rotation of the shock strutabout the trunnion axis of rotation.

C2. The semi-levered landing gear of paragraph C1, wherein movement ofthe retraction mechanism causes rotation of the shock strut such thatthe corresponding movement of the retraction mechanism actuates thetension link assembly to rotate the truck lever about the truck pivotaxis of rotation between the truck lever extended position and the trucklever stowed position.

C3. The semi-levered landing gear of paragraph C1, wherein the shockstrut is substantially uncompressed with the truck lever at the trucklever extended position and with the truck lever at the truck leverstowed position.

C4. The semi-levered landing gear of paragraph C1, wherein the tensionlink assembly is configured so that the truck lever rotates about thetruck pivot axis of rotation during compression of the shock strut.

C5. The semi-levered landing gear of paragraph C1, wherein the tensionlink assembly comprises:

an over-center link having an over-center link first end and anover-center link second end longitudinally spaced from the over-centerlink first end, the over-center link first end defining the tension linkassembly first end and being rotatably coupled to the shock strut aboutan over-center pivot axis; and

a truck link having a truck link first end and a truck link second endlongitudinally spaced from the truck link first end, the truck linkfirst end being rotatably coupled to the over-center link second endabout the tension link assembly rotation axis and the truck link secondend defining the tension link assembly second end and being rotatablycoupled to the truck lever second end.

C6. The semi-levered landing gear of paragraph C5, wherein thepositioning mechanism comprises:

a connecting link having a connecting link first end and a connectinglink second end, the connecting link first end being configured forcoupling to one or more of the airframe and the shock strut;

a first pivot link having a first end and a second end longitudinallyspaced from the first end, the first end of the first pivot link beingrotatably coupled to the shock strut; and

a second pivot link having a first end and a second end longitudinallyspaced from the first end, the first end of the second pivot link beingrotatably coupled to the second end of the first pivot link;

wherein the connecting link second end is coupled to at least one ofproximate the second end of the first pivot link and proximate the firstend of the second pivot link.

C7. The semi-levered landing gear of paragraph C6, wherein:

the second end of the second pivot link is rotatably coupled to theover-center link proximate the over-center link second end so thatmovement of the connecting link causes rotation of the truck link firstend about the over-center pivot axis.

C8. The semi-levered landing gear of paragraph C5, wherein thecorrecting link is a rigid unarticulated link.

C9. The semi-levered landing gear of paragraph C5,

wherein the shock strut rotates about the trunnion axis of rotationbetween a shock strut stowed position and a shock strut extendedposition relative to the airframe.

C10. The semi-levered landing gear of paragraph C1, wherein the trucklever includes but one wheel axis.

C11. The semi-levered landing gear of paragraph C10, wherein the but onewheel axis is proximate the truck lever first end.

C12. The semi-levered landing gear of paragraph C1, wherein rotation ofthe truck lever to the truck lever extended position provides theaircraft with a greater angle of attack at takeoff compared to anaircraft having a same length and but one wheel axis on a shock strut.

C13. The semi-levered landing gear of paragraph C1, wherein rotation ofthe truck lever about the truck pivot axis of rotation provides theaircraft with a same static ground height compared to an aircraft havinga same length and but one wheel axis on a shock strut.

C14. The semi-levered landing gear of paragraph C1, Wherein rotation ofthe truck lever to the truck lever stowed position provides forpositioning of the trunnion axis of rotation of the shock strut closerto a longitudinal centerline of the aircraft compared to an aircrafthaving a shock strut stroke with a same uncompressed length at stowage.

C15. The semi-levered landing gear of paragraph C1, wherein with thetruck lever in the truck lever extended position, the semi-leveredlanding gear provides the aircraft with a predetermined amount of groundcontact vertical load so that the aircraft rotates to a greater angle ofattack at takeoff compared to an aircraft having a same length shockstint and but one wheel axis on the shock strut.

C16. The semi-levered landing gear of paragraph C1, wherein:

the shock stint comprises an outer cylinder and an inner cylinder, wherethe inner cylinder is movable relative to the outer cylinder; and

the truck lever is rotatably coupled to either the inner cylinder or theouter cylinder.

C17. The semi-levered landing gear of paragraph C1, wherein the trucklever comprises a monolithic member.

In the figures, referred to above, solid lines, if any, connectingvarious elements and/or components may represent mechanical, electrical,fluid, optical, electromagnetic, wireless and other couplings and/orcombinations thereof. As used herein, “coupled” means associateddirectly as well as indirectly. For example, a member A may be directlyassociated with a member B, or may be indirectly associated therewith,e.g., via another member C. It will be understood that not allrelationships among the various disclosed elements are necessarilyrepresented. Accordingly, couplings other than those depicted in thedrawings may also exist. Dashed lines, if any, connecting blocksdesignating the various elements and/or components represent couplingssimilar in function and purpose to those represented by solid lines;however, couplings represented by the dashed lines may either beselectively provided or may relate to alternative examples of thepresent disclosure. Likewise, elements and/or components, if any,represented with dashed lines, indicate alternative examples of thepresent disclosure. One or more elements shown in solid and/or dashedlines may be omitted from a particular example without departing fromthe scope of the present disclosure. Environmental elements, if any, arerepresented with dotted lines. Virtual (imaginary) elements may also beshown for clarity. Those skilled in the art will appreciate that some ofthe features illustrated in the figures, may be combined in various wayswithout the need to include other features described in the figures,other drawing figures, and/or the accompanying disclosure, even thoughsuch combination or combinations are not explicitly illustrated herein.Similarly, additional features not limited to the examples presented,may be combined with some or all of the features shown and describedherein.

In FIG. 10, referred to above, the blocks may represent operationsand/or portions thereof and lines connecting the various blocks do notimply any particular order or dependency of the operations or portionsthereof. Blocks represented by dashed lines indicate alternativeoperations and/or portions thereof. Dashed lines, if any, connecting thevarious blocks represent alternative dependencies of the operations orportions thereof. It will be understood that not all dependencies amongthe various disclosed operations are necessarily represented. FIG. 10and the accompanying disclosure describing the operations of themethod(s) set forth herein should not be interpreted as necessarilydetermining a sequence in which the operations are to be performed.Rather, although one illustrative order is indicated, it is to beunderstood that the sequence of the operations may be modified whenappropriate. Accordingly, certain operations may be performed in adifferent order or simultaneously. Additionally, those skilled in theart will appreciate that not all operations described need be performed.

In the foregoing description, numerous specific details are set forth toprovide a thorough understanding of the disclosed concepts, which tinybe practiced without some or all of these particulars. In otherinstances, details of known devices and/or processes have been omittedto avoid unnecessarily obscuring the disclosure. While some conceptswill be described in conjunction with specific examples, it will beunderstood that these examples are not intended to be limiting.

Unless otherwise indicated, the terms “first,” “second,” etc. are usedherein merely as labels, and are not intended to impose ordinal,positional, or hierarchical requirements on the items to which theseterms refer. Moreover, reference to, e.g., a “second” item does notrequire or preclude the existence of, e.g., a “first” or lower-numbereditem, and/or, e.g., a “third” or higher-numbered item.

Reference herein to “one example” means that one or more feature,structure, or characteristic described in connection with the example isincluded in at least one implementation. The phrase “one example” invarious places in the specification may or may not be referring to thesame example.

As used herein, a system, apparatus, structure, article, element,component, or hardware “configured to” perform a specified function isindeed capable of performing the specified function without anyalteration, rather than merely having potential to perform the specifiedfunction after further modification. In other words, the system,apparatus, structure, article, element, component, or hardware“configured to” perform a specified function is specifically selected,created, implemented, utilized, programmed, and/or designed for thepurpose of performing the specified function. As used herein,“configured to” denotes existing characteristics of a system, apparatus,structure, article, element, component, or hardware which enable thesystem, apparatus, structure, article, element, component, or hardwareto perform the specified function without further modification. Forpurposes of this disclosure, a system, apparatus, structure, article,element, component, or hardware described as being “configured to”perform a particular function may additionally or alternatively bedescribed as being “adapted to” and/or as being “operative to” performthat function.

Different examples of the apparatus(es) and method(s) disclosed hereininclude a variety of components, features, and functionalities. Itshould be understood that the various examples of the apparatus(es) andmethod(s) disclosed herein may include any of the components, features,and functionalities of any of the other examples of the apparatus(es)and method(s) disclosed herein in any combination, and all of suchpossibilities are intended to be within the scope of the presentdisclosure.

Many modifications of examples set forth herein will come to mind to oneskilled in the art to which the present disclosure pertains having thebenefit of the teachings presented in the foregoing descriptions and theassociated drawings.

Therefore, it is to be understood that the present disclosure is not tobe limited to the specific examples illustrated and that modificationsand other examples are intended to be included within the scope of theappended claims. Moreover, although the foregoing description and theassociated drawings describe examples of the present disclosure in thecontext of certain illustrative combinations of elements and/orfunctions, it should be appreciated that different combinations ofelements and/or functions may be provided by alternative implementationswithout departing from the scope of the appended claims. Accordingly,parenthetical reference numerals in the appended claims, if any, arepresented for illustrative purposes only and are not intended to limitthe scope of the claimed subject matter to the specific examplesprovided in the present disclosure.

1. A semi-levered landing gear comprising: a shock strut having an innercylinder and an outer cylinder, the Shod(strut configured for couplingto an airframe of an aircraft; a truck lever having a truck lever firstend and a truck lever second end longitudinally spaced from the trucklever first end, the truck lever being rotatably coupled to the shockstrut about a truck pivot axis of rotation that is disposed between thetruck lever first end and the truck lever second end; a tension linkassembly having a tension link assembly first end, a tension linkassembly second end, and at least one tension link assembly rotationaxis disposed between the tension link assembly first end and thetension link assembly second end, the tension link assembly first endbeing coupled to the Shod(strut outer cylinder, and the tension linkassembly second end being coupled to the truck lever second end; and apositioning mechanism being configured for coupling to one or more ofthe airframe and the shock strut and being coupled to the tension linkassembly proximate the tension link assembly first end; wherein thetension link assembly is configured to rotate the truck lever about thetruck pivot axis of rotation between a truck lever extended position anda truck lever stowed position.
 2. The semi-levered landing gear of claim1, wherein the Shod(strut is substantially uncompressed with the trucklever at the truck lever extended position and with the truck lever atthe truck lever stowed position.
 3. The semi-levered landing gear ofclaim 1, wherein the tension link assembly is configured so that thetruck lever rotates about the truck pivot axis of rotation duringcompression of the shock strut.
 4. The semi-levered landing gear ofclaim 1, wherein the tension link assembly comprises: an over-centerlink having an over-center link first end and an over-center link secondend longitudinally spaced from the over-center link first end, theover-center link first end defining the tension link assembly first endand being rotatably coupled to the shock strut about an over-centerpivot axis; and a truck link having a truck link first end and a trucklink second end longitudinally spaced from the truck link first end, thetruck link first end being rotatably coupled to the over-center linksecond end about the tension link assembly rotation axis and the trucklink second end defining the tension link assembly second end and beingrotatably coupled to the truck lever second end.
 5. The semi-leveredlanding gear of claim 4, wherein the positioning mechanism comprises: aconnecting link having a connecting link first end and a connecting linksecond end, the connecting link first end being configured for couplingto one or more of the airframe and the shock strut; a first pivot linkhaving a first end and a second end longitudinally spaced from the firstend, the first end of the first pivot link being rotatably coupled tothe shock strut; and a second pivot link having a first end and a secondend longitudinally spaced from the first end, the first end of thesecond pivot link being rotatably coupled to the second end of the firstpivot link; wherein the connecting link second end is coupled to atleast one of proximate the second end of the first pivot link andproximate the first end of the second pivot link.
 6. The semi-leveredlanding gear of claim 5, wherein the second end of the second pivot linkis rotatably coupled to the over-center link proximate the over-centerlink second end so that movement of the connecting link causes rotationof the truck link first end about the over-center pivot axis.
 7. Thesemi-levered landing gear of claim 1, further comprising: a retractionmechanism coupled to the airframe; wherein the shock strut includes atrunnion, the trunnion being rotatably coupled to the airframe at atrunnion axis of rotation so that the shock strut rotates about thetrunnion axis of rotation between a shock strut stowed position and ashock strut extended position relative to the airframe; and wherein thepositioning mechanism is coupled to the retraction mechanism so thatrotation of the truck lever about the truck pivot axis of rotation,between the truck lever extended position and the truck lever stowedposition, is mechanically slaved to rotation of the shock strut aboutthe trunnion axis of rotation.
 8. The semi-levered landing gear of claim1, wherein the truck lever includes but one wheel axis.
 9. Thesemi-levered landing gear of claim 1, wherein the track lever comprisesa monolithic member.
 10. An aircraft comprising: an airframe; and asemi-levered landing gear including a shock strut coupled to theairframe; a truck lever having a truck lever first end and a truck leversecond end longitudinally spaced from the truck lever first end, thetruck lever being rotatably coupled to the shock strut about a truckpivot axis of rotation that is disposed between the truck lever firstend and the truck lever second end; a tension link assembly having atension link assembly first end, a tension link assembly second end andat least one tension link assembly rotation axis disposed between thetension link assembly first end and the tension link assembly secondend, the tension link assembly first end coupled to the shock strut, andthe tension link assembly second end being coupled to the truck leversecond end; a positioning mechanism coupled to one or more of theairframe and the shock strut and being coupled to the tension linkassembly proximate the tension link assembly first end; wherein thetension link assembly is configured to rotate the truck lever about thetruck pivot axis of rotation between a truck lever extended position anda truck lever stowed position.
 11. The aircraft of claim 10, whereinrotation of the truck lever to the truck lever extended positionprovides the aircraft with a greater angle of attack at takeoff comparedto an aircraft having a same length and but one wheel axis on a shockstrut.
 12. The aircraft of claim 10, wherein rotation of the truck leverabout the truck pivot axis of rotation provides the aircraft with a samestatic ground height compared to an aircraft having a same length shockstrut and but one wheel axis on the shock strut.
 13. The aircraft ofclaim 10, wherein the shock strut is substantially uncompressed with thetruck lever at the truck lever extended position and with the trucklever at the truck lever stowed position.
 14. The aircraft of claim 10,wherein the tension link assembly is configured so that the truck leverrotates about the truck pivot axis of rotation during compression of theshock strut.
 15. The aircraft of claim 10, wherein the tension linkassembly comprises: an over-center link having an over-center link firstend and an over-center link second end longitudinally spaced from theover-center link first end, the over-center link first end defining thetension link assembly first end and being rotatably coupled to the shockstrut about an over-center pivot axis; and a truck link having a trucklink first end and a truck link second end longitudinally spaced fromthe truck link first end, the truck link first end being rotatablycoupled to the over-center link second end about the tension linkassembly rotation axis and the track link second end defining thetension link assembly second end and being rotatably coupled to thetruck lever second end.
 16. A semi-levered landing gear comprising: ashock strut coupled to an airframe of an aircraft about a trunnion axisof rotation; a retraction mechanism coupled to the airframe; a trucklever having a truck lever first end and a truck lever second endlongitudinally spaced from the truck lever first end, the truck leverbeing rotatably coupled to the shock strut about a truck pivot axis ofrotation that is disposed between the truck lever first end and thetruck lever second end; a tension link assembly having a tension linkassembly first end, a tension link assembly second end and at least onetension link assembly rotation axis disposed between the tension linkassembly first end and the tension link assembly second end, the tensionlink assembly first end being coupled to the shock strut, and thetension link assembly second end being coupled to the truck lever secondend; and a positioning mechanism being configured for coupling to one ormore of the airframe; and the shock strut and being coupled to thetension link assembly proximate the tension link assembly first end;wherein rotation of the truck lever about the truck pivot axis ofrotation between a truck lever extended position and a truck leverstowed position is mechanically slaved to rotation of the shock strutabout the trunnion axis of rotation.
 17. The semi-levered landing gearof claim 16, wherein movement of the retraction mechanism causesrotation of the shock strut such that the movement of the retractionmechanism actuates the tension link assembly to rotate the truck leverabout the truck pivot axis of rotation between the truck lever extendedposition and the truck lever stowed position.
 18. The semi-leveredlanding gear of claim 16, wherein the shock strut is substantiallyuncompressed with the truck lever at the truck lever extended positionand with the truck lever at the truck lever stowed position.
 19. Thesemi-levered landing gear of claim 16, wherein the tension link assemblycomprises: an over-center link having an over-center link first end andan over-center link second end longitudinally spaced from theover-center link first end, the over-center link first end defining thetension link assembly first end and being rotatably coupled to the shockstrut about an over-center pivot axis; and a truck link having a trucklink first end and a truck link second end longitudinally spaced fromthe truck link first end, the truck link first end being rotatablycoupled to the over-center link second end about the tension linkassembly rotation axis and the truck link second end defining thetension link assembly second end and being rotatably coupled to thetruck lever second end.
 20. The semi-levered landing gear of claim 19,wherein the positioning mechanism comprises: a connecting link having aconnecting link first end and a connecting link second end, theconnecting link first end being configured for coupling to one or moreof the airframe and the shock strut; a first pivot link having a firstend and a second end longitudinally spaced from the first end, the firstend of the first pivot link being rotatably coupled to the shock strut;and a second pivot link having a first end and a second endlongitudinally spaced from the first end, the first end of the secondpivot link being rotatably coupled to the second end of the first pivotlink; wherein the connecting link second end is coupled to at least oneof proximate the second end of the first pivot link and proximate thefirst end of the second pivot link.